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LAB 14: THE EFFECTIVENESS OF ANTACIDS. Jacqueline. The purpose of the experiment was to determine the relative basicity of Tums, Rolaids, Walgreens Tablet and Walgreens Antacid Liquid. An acid base titration was used to determine the amount of HCl needed to titrate one serving of each antacid product. Using the average of two trials, 2.3mL HCl were needed to titrate one serving of liquid antacid, 2.1mL of HCl were needed to titrate one serving of Rolaids, 1.6mL HCl were needed to titrate one serving of Tums, and 1.1mL HCl were needed to titrate one serving of Walgreens tablet. The true values, calculated using the amount of active bases in one serving of each product, affirmed Rolaids as the most basic, antacid liquid as the second most basic, and Tums and Walgreens tablet having the same lowest basicity. Even though the percent accuracy error for the experiment proved to be 98% for the Tums and antacid liquid, and 99% for the Rolaids and Walgreens tablet, the true order of basicity was close to the order deduced solely from the data.

Key words: acid-base titration, double replacement reaction, solubility, antacids, pH

Results Tables:

TABLE FIVE: PERCENT OF SERVING USED




Trial 1
Trial 2



Tums Tablet
50%
49%



Rolaids Tablet
49%
50%



Walgreens Tablet
51%
51%



Liquid Antacid
43%
80%









TABLE SIX: AMOUNT OF HCl USED IN TITRATION




Trial 1
Trial 2



Tums Tablet
.98mL
.56mL



Rolaids Tablet
.91mL
1.13mL



Walgreens Tablet
.32mL
.80mL



Antacid Liquid
1.05mL
1.74mL









TABLE SEVEN: ACID NEEDED TO TITRATE A FULL SERVING ACCORDING TO DATA GATHERED

Trial 1
Trial 2
Average


Tums Tablet
2.0mL/tablet
1.1mL/tablet
1.6mL/tablet


Rolaids Tablet
1.9mL/tablet
2.3mL/tablet
2.1mL/tablet


Walgreens Tablet
.63mL/tablet
1.6mL/tablet
1.1mL/tablet


Antacid Liquid
2.4mL/serving
2.2mL/serving
2.3mL/serving








TABLE EIGHT: ACTUAL ACID NEEDED TO TITRATE A FULL SERVING



HCl needed




Tums Tablet
100.mL




Rolaids Tablet
148mL




Walgreens Tablet
100.mL




Antacid Liquid
146mL










TABLE NINE: PERCENT ACCURACY ERROR BASED ON TABLE 8




% Accuracy Error




Tums Tablet
98%




Rolaids Tablet
99%




Walgreens Tablet
99%




Antacid Liquid
98%










*Calculations for tables 5-9: see lab notebook




JOURNAL ARTICLE:
Yang YX, Lewis JD, Epstein S, Metz DC. 2006 December 27. Long-term proton pump
inhibitor therapy and risk of hip fracture. JAMA. 296(24): 2947-2953.
http://jama.ama-assn.org/cgi/content/full/296/24/2947